Cell differentiation describes the process by which a cell is destined to become a particular type of cell, according to the Department of Biology at Kenyon College. The zygote is a cell formed from the union of sperm and an egg and is considered totipotent, meaning it can develop into any type of cell in the body. The first few cell divisions from this zygote are also totipotent.
All cells of the human body contain all of the genetic material needed to form a human being, says the Biology Department at Kenyon College. With cell differentiation, not all genes are turned on in every cell. What the cell becomes is determined by various factors. Sometimes, certain cellular components just move to one side of the cell before the cell divides, creating an unequal distribution of the components in the daughter cells. Most of the time, however, a signal from another cell or from the cell's environment causes a cell to differentiate.
Stem cells are special cells that have not yet differentiated into any specific cell, according to the National Institutes of Health. Embryonic stem cells come from embryos, whereas adult stem cells derive from adults. Another type of stem cell is the induced pluripotent stem cell, which is a differentiated cell that returns to an undifferentiated state after being stimulated.